In one type of gas turbine engine, forward and aft fans are joined to respective drum rotors of a counter-rotating power turbine for being powered thereby. A first rotor shaft joins the outer drum to the aft fan, and a second rotor shaft joins the inner drum to the forward fan and extends concentrically inside the first shaft. The first and second shafts are suitably supported by bearings to stationary frames in the engine.
Conventional bearings typically are provided with lubrication oil through oil injectors located adjacent thereto. However, since the second shaft is disposed inside the first shaft and rotates in an opposite direction, the required bearings therebetween are not readily accessible for supplying lubrication oil thereto.